A computer network is a collection of interconnected computing devices that exchange data and share resources. Networks that primarily utilize data link layer devices are often referred to as layer two (L2) networks. In a L2 network, e.g., an Ethernet network, customer devices, including servers, printers, computers, and the like, are connected by one or more data link layer devices referred to as access nodes. The access nodes, such as digital subscriber line access multiplexers (DSLAMs) or cable modem termination systems (CMTS), forward L2 packets to devices within the network.
Recently, network service providers have offered systems that provide L2 connectivity between multiple, geographically separate L2 customer networks. One mechanism by which network service providers provide L2 connectivity to their customers is by utilization of Virtual Local Area Networks (VLANs). A service provider may associate different VLANs with different customers so that L2 packets and control information for the networks are logically separate for the customers. Each VLAN provides a connection between devices assigned to the VLAN, and each of the VLANs may essentially be treated as an independent layer two (L2) network. A device assigned to one VLAN can communicate with other devices on that VLAN but may be unable to communicate with devices on a separate VLAN. L2 packets for different VLANs may be correctly forwarded within a network by appending VLAN tags to the packets to designate the VLAN to which each packet belongs.
In L2 wholesale computer networks, the network service provider contracts with a network operator to utilize existing infrastructure, such as copper telephone lines, to deliver data or Internet services to the customers of the network operator. Often, the service provider in this arrangement is referred to as an Internet service provider (ISP). Using the existing network infrastructure owned and operated by the network operator, the ISP provides data or Internet services to which one or more customers of the network operator may subscribe. In this arrangement, the network operator may contract with a number of different ISPs to provide customers of the network operator with a choice of services at competitive prices. This network operator is considered a L2 wholesaler in that the network operator offers L2 connectivity for use by any ISP.